Description
In laser-driven inertial confinement fusion (ICF), the implosion performance is limited by scattered energy due to laser–plasma instabilities (LPIs). Our previous study explored how these are influenced by increasing laser bandwidth, using the upgraded PHELIX laser system. We compared monochromatic and broadband frequency-doubled Nd:glass pulses at $527\,nm$, with pulse durations of $2\,ns$ and bandwidths reaching up to $0.5%$. Broadband pulses resulted in reduced two-plasmon decay and stimulated Brillouin scattering, while simultaneously enhancing stimulated Raman scattering and strengthening hot-electron signals [1].
Here, we present results from a new experiment campaign extending our study. Measurements were performed over a significantly broader laser-intensity range, with good signal levels for $10^{14}-10^{16}\,W/cm^2$, enabling a more systematic comparison with theory. The plasma density was directly measured using interferometry to better constrain the experimental conditions. For some instances a preheated plasma was produced by a low-intensity pedestal pulse to study its effect on LPI.
The expanded parameter range, improved plasma diagnostics, and the introduction of a controllable pedestal pulse provide new insight into the role of broadband laser pulses in driving LPI in ICF experiments.
References
- C. Kanstein et.al., 2025, Experimental study of laser plasma instabilities with broadband laser pulses at the GSI PHELIX laser facility, Plasma Phys. Control. Fusion 67 115027